Production of metal airscrews or propellers



June 5, '1 923. 1,457,844

H. LEITNER PRODUCTION OF METAL AIRSCREWS 0R PROPELLERS Filed Jan. 161922 d In entor June 5,

Y LEITNEB, OF LONDON, ENGLAND.

rnonu'cnon or mar. cnnws 0a r normlm.

Application filed January 16, 1922. Serial No. 529,761.

I '0 all whom it may concern-L Be it lmown that I, HENRY Lnrrm, a subectof the King of Great Britain, residing at egent House, Kingsway London,England, have invented newan useful Improvements in the Production ofMetal Airscrews or Propellers, of which the following is aspecification.

This invention relates to a novel, eifective and economical method ofmanufacturin metal airscrews or propellers of the kind comprising hollowblades eaclr of which consists of an outer sheath strengthened withinternal laminations.

According to the invention I'first cut out the outer sheath or sheet andthe laminations for each half blade and then weld the said sheet andlaminations of each half blade together at the edges while still flat.The sheet and laminations thus welded are then-raised to a temperatureof say 850 0., and,, ;while still hot, are premd between dies to impartto them the required curvature. The dies are in practice, stepped inorder to conform to the contour of the laminations.

The heating of the half blade not only enables it tobe shaped in thedies but also normalizes the weld between the outer sheet and thelaminations The half blades produced as above described are secured toher to form a complete blade in the ordinary way.

To enable the invention to be fully understood I will describe it byreference to the'accompanying drawing, in which Figures 1, 2 and 3 are,respectively, plan views of the flat blanks for forming the outer sheathor sheet and two inner laminations of one half of a propeller blade madein accordance with t e invention.

Figure 4 is asimilar view showing the said three blanks superposed intheir proper relative positions to be welded at their edges to form thehalf blade, and V of metal air-screws or propellers efthe kind Figure 5is a perspective view showing the said three blanks after being pressedbetween dies to the re uired curvature.

Figures 6, 8, 9 and 10 are sections drawn to a larger scale of the halfblade when pressed, the sections being taken on "the lines 6-6, Z7, 88,9-9 and 1010 respectively, Figure 4.

a, b, 0 Figures 1 to 4 inclusive indicate reg spectively, the flatblanks of the outer sheet,

t e intermediate lamina and the inner lamina of the half pro ellerblade, the said parts be-v ing superpose as indicated in the latterfiure, and welded or otherwise secured toget or at their edges, as at d Fires 6 to 8., The half blade is then preferab y raised to a temperatureof, say. 850 C., and while hot, pressed between dies to impart to theseveral layers the required curvature, that form necessary for the backof the blade being shown in full lines Figures 6 to 10, whilst thatreguired for the front or face of the blade is inicaged by the dottedsections in Figures 6 to 1 The half blades indicated respectively by thefull lines and dotted lines in Figures 6 to 10 are then secured togetherto form the complete blade in the ordinary way.

C aim:

A method of constructing the hollow blades hereinbefore referred, toconsistin in first cutting the outer sheath or sheet an the laminationsfor each half blade from flat sheet metal, then welding such outer sheetnd laminations together at the edges, then" bjecting. such welded sheetsto a temperature to ena 1e them to be pressed between dies to the reuired curvature and finally securing the he f blades to ther at theiredges, substantially as descri d.

HENRY LEITNER.

